1. Field of the Invention
The present invention relates to an apparatus for removing lead characters from a cassette which stores an image information recording medium carrying recorded radiation image information when the cassette is loaded into a processor.
2. Description of the Related Art
Generally, it has been the customary practice to apply a radiation such as X-rays, for example, to a subject such as a human body to record radiation image information of the subject on a photographic film such as an X-ray photographic film. The photographic film is then subjected to an image developing process to produce a visible image of the subject on the photographic film. The visible image is used for a medical diagnosis or the like.
The photographic film is usually stored in a cassette, and the cassette with the photographic film stored therein is loaded into an exposure apparatus. In the exposure apparatus, X-rays that have passed through a subject are applied to the photographic film through the cassette. Thereafter, the cassette is removed from the exposure apparatus and then loaded into an image developing apparatus (processor) in which the photographic film is delivered from the cassette and subjected to the image developing process.
Lead characters representing various items of information of the subject, e.g., the name, the date of exposure, and the recorded region, are often applied to the cassette. Therefore, the radiation image information of the subject and the various items of information of the subject as represented by the lead characters are recorded on the photographic film in the cassette, allowing the photographic film to be handled with ease.
There has been known a radiation image recording and reproducing system for recording radiation image information of a subject, such as a human body, using a stimulable phosphor, and either reproducing the recorded radiation image information on a photosensitive medium such as a photographic film or the like or displaying the recorded radiation image information on a cathode-ray tube or other display units.
When a radiation energy such as X-rays, .alpha.-rays, .gamma.-rays, electron beams, ultraviolet radiation, or the like is applied to a certain phosphor, it stores part of the applied radiation energy. When stimulating light such as visible light is subsequently applied to the phosphor, the phosphor emits light depending the stored radiation energy. Such a phosphor is referred to as a stimulable phosphor.
A stimulable phosphor is usually used in the form of a sheet which is referred to as a stimulable phosphor sheet. Such a stimulable phosphor sheet is stored in a cassette. Lead characters representing various items of information of a subject, whose radiation image information has been recorded on a stimulable phosphor sheet, are also applied to a cassette which stores the stimulable phosphor sheet.
When a cassette storing a photographic film on which radiation image information has been recorded is loaded into an image developing apparatus, or when a cassette storing a stimulable phosphor sheet on which radiation image information has been recorded is loaded into an image information reading apparatus (processor), it is necessary to remove the lead characters from the cassette. However, lead characters are occasionally left unremoved from cassettes which store photographic films or stimulable phosphor sheets. If such lead characters are not removed from a cassette, then the lead characters remain in the processor and tend to fall in the processor, causing a feed failure of the photographic film or stimulable phosphor sheet.
Another possibility is that a new photographic film or stimulable phosphor sheet may be placed into a cassette which carries lead characters about a previous subject, and may be exposed to a radiation image of a new subject. When this happens, the various items of information of the previous subject as represented by the existing lead characters are recorded on the new photographic film or stimulable phosphor sheet, resulting in a discrepancy between the newly recorded radiation image information and the previously recorded various items of information.